Capacity control valve and control method of capacity control valve

ABSTRACT

A capacity control valve ( 1 ) includes a valve main body ( 10 ) having a first communication passage ( 11 ), a second communication passage ( 12 ), a third communication passage ( 13 ), and a main valve seat ( 15   a ), a valve element ( 20 ) having an intermediate communication passage ( 29 ), a main valve portion ( 21   c ), and an auxiliary valve portion ( 23   d ), and a solenoid ( 30 ) having a plunger ( 35 ) that drives a first rod ( 136 ) and a second rod ( 36 ). The first rod ( 136 ) opens and closes the main valve portion ( 21   c ), and the second rod ( 36 ) opens and closes the auxiliary valve portion. The capacity control valve is capable of efficiently discharging a liquid coolant irrespective of pressure of a suction chamber and lowering drive force of a compressor at a liquid coolant discharging operation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase under 35 U.S.C. § 371 ofInternational Application PCT/JP2019/001569, filed Jan. 21, 2019, whichclaims priority to Japanese Patent Application No. JP2018-008481, filedJan. 22, 2018. The International Application was published under PCTArticle 21(2) in a language other than English.

TECHNICAL FIELD

The present invention relates to a capacity control valve and a methodfor controlling the capacity control valve used for controlling a flowrate or pressure of a variable capacity compressor.

BACKGROUND ART

As the variable capacity compressor, for example, a swash plate typevariable capacity compressor used in an air conditioning system of anautomobile, etc. includes a rotation shaft to be driven and rotated byrotation force of an engine, a swash plate coupled to the rotation shaftso that a tilting angle is variable, and compressing pistons coupled tothe swash plate, etc., and is to change strokes of the pistons andcontrol a discharge amount of a coolant by changing the tilting angle ofthe swash plate.

This tilting angle of the swash plate can be continuously changed byappropriately controlling pressure in a control chamber by using acapacity control valve to be driven and opened/closed by electromagneticforce while utilizing suction pressure of a suction chamber to which thecoolant is sucked in, discharge pressure of a discharge chamber fromwhich the coolant pressurized by the pistons is discharged, and controlchamber pressure of the control chamber (crank chamber) in which theswash plate is housed, and by adjusting a balance state of pressureacting on both surfaces of the pistons.

FIG. 5 shows an example of such a capacity control valve. A capacitycontrol valve 160 includes a valve portion 170 having a second valvechamber 182 which communicates with the discharge chamber of thecompressor via a second communication passage 173, a first valve chamber183 which communicates with the suction chamber via a firstcommunication passage 171, and a third valve chamber 184 whichcommunicates with the control chamber via a third communication passage174, a pressure-sensitive body 178 arranged in the third valve chamber,the pressure-sensitive body to be extended and contracted by peripheralpressure, the pressure-sensitive body having a valve seat body 180provided in a free end in the extending and contracting direction, avalve element 181 having a second valve portion 176 which opens andcloses a valve hole 177 providing communication between the second valvechamber 182 and the third valve chamber 184, a first valve portion 175which opens and closes the first communication passage 171 and adistribution groove 172, and a third valve portion 179 which opens andcloses the third valve chamber 184 and the distribution groove 172 byengagement with and disengagement from the valve seat body 180 in thethird valve chamber 184, a solenoid portion 190 which applieselectromagnetic drive force to the valve element 181, etc.

In this capacity control valve 160, without providing a clutch mechanismin the variable capacity compressor, in a case where the need forchanging the control chamber pressure arises, the pressure (controlchamber pressure) Pc in the control chamber and the suction pressure Ps(suction pressure) can be controlled by providing communication betweenthe discharge chamber and the control chamber (hereinafter, referred toas the “conventional art”. See Patent Document 1, for example).

CITATION LIST Patent Documents

Patent Document 1: JP 5167121 P

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In the conventional art, in a case where the swash plate type variablecapacity compressor is stopped for a long time, a liquid coolant (madeby cooling and liquefying a coolant during abandonment) is accumulatedin the control chamber (crank chamber). Thus, even when the compressoris started up in this state, it is not possible to ensure a dischargeamount as it is set. Therefore, in order to perform desired capacitycontrol immediately after start-up, there is a need for discharging theliquid coolant of the control chamber (crank chamber) as soon aspossible.

As shown in FIG. 6, the conventional capacity control valve 160 includesa function of discharging the liquid coolant in order to discharge theliquid coolant of the control chamber (crank chamber) as soon aspossible at the time of start-up. That is, in a case where the variablecapacity compressor is stopped and abandoned for a long time and thenstarted up, the high-pressure liquid coolant accumulated in the controlchamber (crank chamber) flows into the third valve chamber 184 from thethird communication passage 174. Then, the pressure-sensitive body 178is contracted, a part between the third valve portion 179 and the valveseat body 180 is opened, and from the third valve chamber 184 throughthe auxiliary communication passage 185, the communication passage 186,and the distribution groove 172, the liquid coolant is discharged to thedischarge chamber from the control chamber (crank chamber) via thesuction chamber and rapidly gasified, so that it is possible to make acooling operation state for a short time.

However, in the above conventional art, at an initial stage of a liquidcoolant discharging process, pressure of the control chamber is high andhence an opening degree of the third valve portion 179 is large. Thus,it is possible to efficiently discharge the liquid coolant. However, asdischarge of the liquid coolant progresses and the pressure of thecontrol chamber is lowered, the opening degree of the third valveportion is decreased. Thus, there is a problem that it takes time todischarge the liquid coolant.

Conventionally, at the time of a liquid coolant discharging operation,focus is placed only on how quickly the discharge of the liquid coolantis completed. Thus, control of reducing an engine load is not performedat the time of the liquid coolant discharging operation. However, whenthe liquid coolant discharging operation is performed with a high engineload, the engine load is further increased, and there is also a problemthat energy efficiency of the entire automobile is lowered.

The present invention is achieved to solve the problems of the aboveconventional art, and an object of the present invention is to provide acapacity control valve and a method for controlling a capacity controlvalve, capable of, in the capacity control valve that controls a flowrate or pressure of a variable capacity compressor in accordance with avalve opening degree of a valve portion, stably controlling an openingdegree of a main valve portion at the time of control, efficientlydischarging a liquid coolant irrespective of pressure of a suctionchamber, shifting to a cooling operation for a short time, and furtherlowering drive force of the compressor at a liquid coolant dischargingoperation.

Means for Solving Problem

In order to solve the foregoing problems, a capacity control valveaccording to a first aspect of the present invention is a capacitycontrol valve that controls a flow rate or pressure of a variablecapacity compressor in accordance with a valve opening degree of a valveportion, the capacity control valve being characterized by including avalve main body having a first communication passage through which afluid of first pressure passes, a second communication passage arrangedadjacent to the first communication passage, the second communicationpassage through which a fluid of second pressure passes, a thirdcommunication passage through which a fluid of third pressure passes,and a main valve seat arranged in a valve hole which providescommunication between the second communication passage and the thirdcommunication passage, a valve element having an intermediatecommunication passage providing communication between the firstcommunication passage and the third communication passage, a main valveportion to be separated from and connected to the main valve seat so asto open and close the valve hole, and an auxiliary valve portionarranged in the intermediate communication passage, and a solenoidhaving a plunger that drives a first rod and a second rod, characterizedin that the first rod opens and closes the main valve portion, and thesecond rod opens and closes the auxiliary valve portion.

According to the first aspect, in a control state, the first rod opensand closes the main valve portion so as to control a capacity controlvalve, and in liquid coolant discharge, the second rod maintains anopening degree of the auxiliary valve portion in a fully opened state,so that it is possible to efficiently discharge a liquid coolantirrespective of pressure of a suction chamber.

The capacity control valve according to a second aspect of the presentinvention is characterized in that one end of the first rod is driven bythe plunger via a first biasing member, and the other end is connectedto the valve element.

According to the second aspect, the first rod transmits drive force ofthe solenoid to the valve element, so that it is possible to reliablydrive the valve element.

The capacity control valve according to a third aspect of the presentinvention is characterized in that one end of the second rod isconnected to the plunger, and the other end is connected to an auxiliaryvalve seat to be separated from and connected to the auxiliary valveportion.

According to the third aspect, the second rod can open and close theauxiliary valve portion irrespective of the pressure of the suctionchamber, so that it is possible to efficiently discharge the liquidcoolant.

The capacity control valve according to a fourth aspect of the presentinvention is characterized in that the solenoid further includes a corearranged between the plunger and the valve main body, an electromagneticcoil, and a second biasing member arranged between the plunger and thecore.

According to the fourth aspect, by the second biasing member arrangedbetween the plunger and the core, it is possible to reliably bias thevalve element in the valve opening direction of the main valve portion.

The capacity control valve according to a fifth aspect of the presentinvention is characterized in that the first pressure is suctionpressure of the variable capacity compressor, the second pressure isdischarge pressure of the variable capacity compressor, and the thirdpressure is pressure of a crank chamber of the variable capacitycompressor. The capacity control valve according to a sixth aspect ofthe present invention is characterized in that the first pressure ispressure of a crank chamber of the variable capacity compressor, thesecond pressure is discharge pressure of the variable capacitycompressor, and the third pressure is suction pressure of the variablecapacity compressor.

According to the fifth or sixth aspect, it is possible to respond tovarious variable capacity compressors.

In order to solve the foregoing problems, a method for controlling acapacity control valve according to a seventh aspect of the presentinvention is a method for controlling a capacity control valve,characterized by including the step of making the main valve portionfrom a closed state to an opened state when the auxiliary valve portionis in an opened state.

According to the seventh aspect, in a state where biasing force of thepressure-sensitive body does not act on the valve element at the time ofthe liquid coolant discharge, the main valve portion is opened and aflow rate from a discharge chamber to a control chamber is increased, sothat it is possible to reduce the load of the compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front sectional view of a capacity control valve accordingto the present invention.

FIG. 2 is an enlarged view of part of a valve main body, a valveelement, and a solenoid of FIG. 1 showing the capacity control valve atthe time of turning off the solenoid.

FIG. 3 is an enlarged view of part of the valve main body, the valveelement, and the solenoid of FIG. 1 showing a control state of thecapacity control valve.

FIG. 4 is an enlarged view of part of the valve main body, the valveelement, and the solenoid of FIG. 1 showing a state of the capacitycontrol valve at the time of liquid coolant discharge.

FIG. 5 is a front sectional view showing a conventional capacity controlvalve.

FIG. 6 shows a state of the conventional capacity control valve at thetime of liquid coolant discharge.

DESCRIPTION OF EMBODIMENTS

Hereinafter, with reference to the drawings, a mode for carrying out thepresent invention will be described illustratively based on anembodiment. However, the dimensions, materials, shapes, relativepositions, etc. of constituent parts described in this embodiment arenot limited only to themselves unless otherwise described particularlyexplicitly.

With reference to FIGS. 1 to 4, a capacity control valve according tothe present invention will be described. In FIG. 1, the reference sign 1denotes a capacity control valve. The capacity control valve 1 is mainlyformed by a valve main body 10, a valve element 20, a pressure-sensitivebody 24, and a solenoid 30.

Hereinafter, with reference to FIGS. 1 and 2, respective constituentelements of the capacity control valve 1 will be described. The valvemain body 10 is made of metal such as brass, iron, aluminum, stainless,or synthetic resin, etc. The valve main body 10 is a cylindrical hollowmember having a through hole which passes through in the axialdirection. In sections of the through hole, a first valve chamber 14, asecond valve chamber 15 adjacent to the first valve chamber 14, and athird valve chamber 16 adjacent to the second valve chamber 15 arecontinuously arranged.

A second communication passage 12 is continuously provided in the secondvalve chamber 15. This second communication passage 12 communicates withthe inside of a discharge chamber (not shown) of a variable capacitycompressor so that a fluid of discharge pressure Pd (second pressureaccording to the present invention) can flow in from the second valvechamber 15 to the third valve chamber 16 by opening and closing thecapacity control valve 1.

A third communication passage 13 is continuously provided in the thirdvalve chamber 16. The third communication passage 13 communicates with acontrol chamber (not shown) of the variable capacity compressor so thatthe fluid of discharge pressure Pd flowing in from the second valvechamber 15 to the third valve chamber 16 by opening and closing thecapacity control valve 1 flows out to the control chamber (crankchamber) of the variable capacity compressor and a fluid of controlchamber pressure Pc (third pressure according to the present invention)flowing into the third valve chamber 16 flows out to a suction chamberof the variable capacity compressor via an intermediate communicationpassage 29 to be described later and through the first valve chamber 14.

Further, a first communication passage 11 is continuously provided inthe first valve chamber 14. This first communication passage 11 leads afluid of suction pressure Ps (first pressure according to the presentinvention) from the suction chamber of the variable capacity compressorto the pressure-sensitive body 24 via the intermediate communicationpassage 29 to be described later, and controls the suction pressure ofthe compressor to a set value.

Between the first valve chamber 14 and the second valve chamber 15, ahole portion 18 having a diameter smaller than a diameter of any ofthese chambers is continuously formed. This hole portion 18 slides witha labyrinth 21 f to be described later and forms a seal portion thatseals a part between the first valve chamber 14 and the second valvechamber 15. Between the second valve chamber 15 and the third valvechamber 16, a valve hole 17 having a diameter smaller than a diameter ofany of these chambers is continuously provided. A main valve seat 15 ais formed around the valve hole 17 on the second valve chamber 15 side.This main valve seat 15 a is separated from and connected to a mainvalve portion 21 c to be described later so as to control opening andclosing of a Pd-Pc flow passage providing communication between thesecond communication passage 12 and the third communication passage 13.

The pressure-sensitive body 24 is arranged in the third valve chamber16. One end portion of a metal bellows 24 a of this pressure-sensitivebody 24 is combined to a partition adjusting portion 24 f in a sealedstate. This bellows 24 a is made of phosphor bronze, stainless, etc. anda spring constant of the bellows is designed to be a predeterminedvalue. An internal space of the pressure-sensitive body 24 is vacuum orthe air exists in the internal space. Pressure acts on a valid pressurereceiving area of the bellows 24 a of this pressure-sensitive body 24 sothat the pressure-sensitive body 24 is extended and contracted. A flangeportion 24 d is arranged on the free end portion side of thepressure-sensitive body 24. By directly pressing this flange portion 24d by a locking portion 26 of a second rod 36 to be described later, thepressure-sensitive body 24 is extended and contracted. That is, asdescribed later, the pressure-sensitive body 24 is extended andcontracted in accordance with the suction pressure Ps led to thepressure-sensitive body 24 via the intermediate communication passage29, and also extended and contracted by pressing force of the second rod36.

The partition adjusting portion 24 f of the pressure-sensitive body 24is sealed, fitted, and fixed so as to close the third valve chamber 16of the valve main body 10. By screwing the partition adjusting portion24 f and fixing by a locking screw (not shown), it is possible to adjustaxial movement of spring force of a compression spring arranged inparallel in the bellows 24 a or the bellows 24 a.

For example, two to six parts of each of the first communication passage11, the second communication passage 12, and the third communicationpassage 13 pass through a peripheral surface of the valve main body 10at equal intervals. Further, attachment grooves for O rings are providedat three points while being separated in the axial direction on an outerperipheral surface of the valve main body 10. O rings 47, 48, 49 thatseal a part between the valve main body 10 and an installment hole of acasing (not shown) fitted to the valve main body 10 are attached to theattachment grooves. Flow passages of the first communication passage 11,the second communication passage 12, and the third communication passage13 are formed as independent flow passages.

Next, the valve element 20 will be described. The valve element 20 ismainly formed by a main valve element 21 which is a cylindrical hollowmember, and an adapter 23. First, the main valve element 21 will bedescribed. The main valve element 21 is a cylindrical hollow member, andthe labyrinth 21 f is formed in a substantially center portion in theaxial direction of an outer peripheral portion of the main valveelement. The main valve element is inserted into the valve main body 10,and the labyrinth 21 f slides on the hole portion 18 between the firstvalve chamber 14 side and the second valve chamber 15 side so as to forma seal portion that seals the first valve chamber 14 and the secondvalve chamber 15. Thereby, the first valve chamber 14 communicating withthe first communication passage 11 and the second valve chamber 15communicating with the second communication passage 12 are formed asindependent valve chambers.

The main valve element 21 is arranged on the first communication passage11 side and on the second communication passage 12 side across thelabyrinth 21 f. The main valve portion 21 c is formed in an end portionof the main valve element 21 arranged on the second communicationpassage 12 side. The main valve portion 21 c is separated from andconnected to the main valve seat 15 a so as to control opening andclosing of the valve hole 17 providing communication between the secondcommunication passage 12 and the third communication passage 13. Themain valve portion 21 c and the main valve seat 15 a form a main valve27 b. A situation where the main valve portion 21 c and the main valveseat 15 a are brought from a contact state into a separate state will beindicated as the main valve 27 b is opened or the main valve portion 21c is opened. A situation where the main valve portion 21 c and the mainvalve seat 15 a are brought from a separate state into a contact statewill be indicated as the main valve 27 b is closed or the main valveportion 21 c is closed. A shut-off valve portion 21 a is formed in anend portion of the main valve element 21 arranged in the first valvechamber 14. When the solenoid 30 to be described later is turned off,the shut-off valve portion 21 a is brought into contact with an endportion 32 c of a core 32 so as to shut off communication between theintermediate communication passage 29 and the first communicationpassage 11. The shut-off valve portion 21 a and the end portion 32 c ofthe core 32 form a shut-off valve 27 a. The shut-off valve portion 21 aand the main valve portion 21 c of the valve element 20 perform openingand closing actions in the opposite directions to each other. Asituation where the shut-off valve portion 21 a and the end portion 32 cof the core 32 are brought from a contact state into a separate statewill be indicated as the shut-off valve 27 a is opened or the shut-offvalve portion 21 a is opened. A situation where the shut-off valveportion 21 a and the end portion 32 c of the core 32 are brought from aseparate state into a contact state will be indicated as the shut-offvalve 27 a is closed or the shut-off valve portion 21 a is closed.

Next, the adapter 23 forming the valve element 20 will be described. Theadapter 23 is mainly formed by a large diameter portion 23 c formed tohave a large diameter by a cylindrical hollow member, and a tube portion23 e formed to have a diameter smaller than the large diameter portion23 c. The tube portion 23 e is fitted to an opening end portion on themain valve portion 21 c side of the main valve element 21 so that thevalve element 20 is formed. Thereby, the intermediate communicationpassage 29 passing through in the axial direction is formed in theinside of the main valve element 21 and the adapter 23, that is, theinside of the valve element 20. An auxiliary valve portion 23 d isformed in an end portion of the large diameter portion 23 c of theadapter 23. The auxiliary valve portion 23 d is brought into contactwith and separated from an auxiliary valve seat 26 c of the lockingportion 26 of the second rod 36 so as to open and close the intermediatecommunication passage 29 providing communication between the firstcommunication passage 11 and the third communication passage 13. Theauxiliary valve portion 23 d and the auxiliary valve seat 26 c form anauxiliary valve 27 c. A situation where the auxiliary valve portion 23 dand the auxiliary valve seat 26 c are brought from a contact state intoa separate state will be indicated as the auxiliary valve 27 c is openedor the auxiliary valve portion 23 d is opened. A situation where theauxiliary valve portion 23 d and the auxiliary valve seat 26 c arebrought from a separate state into a contact state will be indicated asthe auxiliary valve 27 c is closed or the auxiliary valve portion 23 dis closed.

Next, the solenoid 30 will be described. The solenoid 30 mainly includesa first rod 136, the second rod 36, a plunger case 38, anelectromagnetic coil 31, the core 32 formed by a center post 32 a and abase member 32 b, a plunger 35, a plate 34, and a solenoid case 33. Thefirst rod 136 and the second rod 36 are driven in accordance withelectric currents supplied from the outside. The plunger case 38 is abottomed cylindrical hollow member whose one side is open. The plunger35 is arranged movably in the axial direction with respect to theplunger case 38 between the plunger case 38 and the center post 32 aarranged inside the plunger case 38. The core 32 is fitted to the valvemain body 10 and arranged between the plunger 35 and the valve main body10.

An opening end portion of the plunger case 38 is fixed to an innerperipheral portion of the base member 32 b of the core 32 in a sealedstate, and the solenoid case 33 is fixed to an outer peripheral portionof the base member 32 b in a sealed state. The electromagnetic coil 31is arranged in a space surrounded by the plunger case 38, the basemember 32 b of the core 32, and the solenoid case 33 and not broughtinto contact with a coolant. Thus, it is possible to prevent a decreasein insulation resistance.

The first rod 136 is a hollow axial member arranged in the center post32 a of the core 32. The first rod 136 has a clearance from a throughhole 32 e of the center post 32 a of the core 32 so as to be relativelymoved with respect to the core 32. One end portion 136 a of the firstrod 136 is pressed and driven by an end portion 36 m of the second rodfixed to the plunger 35 via a spring 137. A communication groove 136 fis formed in an outer peripheral portion of the other end portion 136 bof the first rod 136, and the end portion 136 b and the main valveelement 21 are fitted and fixed to each other. Since the communicationgroove 136 f is formed in the outer peripheral portion of the endportion 136 b of the first rod 136, even in a state where the endportion 136 b and the main valve element 21 are fitted to each other,the intermediate communication passage 29 is not closed and a flow ofthe coolant is not inhibited.

The second rod 36 is an axial member arranged in the first rod 136. Thesecond rod 36 has a clearance from a through hole 136 e of the first rod136 so as to be relatively moved with respect to the core 32 and thefirst rod 136. One end portion 36 e of the second rod 36 is fixed to theplunger 35, and the locking portion 26 is fitted and fixed to the otherend portion 36 h of the second rod 36.

The locking portion 26 forming part of the second rod 36 will bedescribed. The locking portion 26 is a disc plate shaped member in whicha base portion 26 a is formed and brim portions are formed from the baseportion 26 a on both sides in the axial direction. One of the brimportions functions as the auxiliary valve seat 26 c to be separated fromand connected to the auxiliary valve portion 23 d of the adapter 23, andthe other brim portion functions as a pressing portion 26 d to beseparated from and connected to the flange portion 24 d of thepressure-sensitive body 24 so as to extend and contract thepressure-sensitive body 24. A distribution hole 26 f through which thecoolant is distributed is formed in the base portion 26 a of the lockingportion 26. The locking portion 26 may be integrated with the second rod36 or the locking portion 26 may be fitted and fixed to the second rod36 and integrally formed.

Between the core 32 and the plunger 35, the spring 137 (first biasingmember according to the present invention) that biases and separates theplunger 35 from the core 32, and a spring 37 (second biasing memberaccording to the present invention) are arranged.

The spring 137 is arranged between the plunger 35 and the core 32.Specifically, one end of the spring 137 is in contact with the endportion 136 a of the first rod 136, the other end is in contact with theend portion 36 m of the second rod 36 fixed to the plunger 35, the firstrod 136 and the plunger 35 are biased in the direction in which thefirst rod and the plunger are separated from each other, and the valveelement 20 is biased in the valve closing direction of the main valve 27b. The spring 137 is assembled between the first rod 136 and the secondrod 36 in a state where the spring is compressed by a predeterminedamount from natural length, that is, in a state where the spring has aninitial set load. Thereby, the spring 137 is not deformed with driveforce of the solenoid 30 being not more than the initial set load, andthe first rod 136 and the second rod 36 are integrally moved. The spring137 is deformed upon exceeding the initial set load, and the first rod136 and the second rod are relatively moved. The initial set load of thespring 137 is set to be larger than the drive force of the solenoid 30at the time of controlling the capacity control valve 1. The spring 137may be arranged so that the one end is in contact with the end portion136 a of the first rod 136 and the other end is in contact with theplunger 35.

The spring 37 is arranged between the plunger 35 and the core 32.Specifically, one end of the spring 37 is in contact with an end portionof the center post 32 a, the other end is in contact with an end portionof the plunger 35, and the core 32 and the plunger 35 are biased in thedirection in which the core and the plunger are separated from eachother. An initial set load of the spring 37 is small, the spring 37 isdeformed in proportion to the drive force of the solenoid 30, and thesecond rod 36 is relatively moved with respect to the core 32 inaccordance with the drive force of the solenoid 30.

Actions of the capacity control valve 1 having the configurationdescribed above will be described. A flow passage running from the thirdcommunication passage 13 to the first communication passage 11 throughthe intermediate communication passage 29 will be called as the “Pc-Psflow passage” below. A flow passage running from the secondcommunication passage 12 to the third communication passage 13 throughthe valve hole 17 will be called as the “Pd-Pc flow passage” below.

First, movement of the first rod 136 and the second rod 36 and movementof the valve portions of the valve element 20 will be described. Firstof all, based on FIGS. 1 and 2, the movement of the first rod 136 andthe second rod 36 and the movement of the valve portions of the valveelement 20 in a non-energized state of the solenoid 30 will bedescribed. In a non-energized state, the plunger 35 is pushed upward bybiasing force of the pressure-sensitive body 24 and biasing force of thespring 37 (FIG. 1), the main valve portion 21 c of the valve element 20is fully opened, and the shut-off valve portion 21 a is fully closed.The locking portion 26 of the second rod 36 is brought into contact withthe adapter 23 and the auxiliary valve 27 c is closed.

Next, based on FIG. 3, the movement of the first rod 136 and the secondrod 36 and the movement of the valve portions of the valve element 20 ina state where energization of the solenoid 30 is started from anon-energized state and the main valve 27 b is opened will be described.Since the initial set load of the spring 137 is set to be larger thanthe drive force of the solenoid 30 at the time of controlling thecapacity control valve 1, in a state where the main valve 27 b isopened, the first rod 136 and the second rod 36 are integrally moved ina state where relative positions are maintained. First, whenenergization of the solenoid 30 is started from a non-energized state,the first rod 136 and the second rod 36 are integrally and graduallydriven in the forward direction (direction in which the first rod 136and the second rod 36 pop out from the end portion 32 c of the core 32to the outside). Thereby, the shut-off valve portion 21 a is separatedfrom the end portion 32 c of the core 32, the shut-off valve 27 a isopened from a fully closed state, and the main valve 27 b is graduallynarrowed down from a fully opened state. At the time of controlling thecapacity control valve 1, the valve element 20 connected to the firstrod 136 and the second rod 36 are integrally displaced. Thus, thecapacity control valve 1 can stably control an opening degree of themain valve 27 b.

Further, when the first rod 136 and the second rod 36 are driven in theforward direction, as shown in FIG. 4, the shut-off valve 27 a isbrought into a fully opened state, the main valve portion 21 c isbrought into contact with the main valve seat 15 a, the main valve 27 bis brought into a fully closed state, and the movement of the first rod136 and the valve element 20 is stopped. That is, when the solenoid 30is further driven in a state where the first rod 136 and the valveelement 20 are stopped, that is, in a state where the main valve 27 b isfully closed, the drive force of the solenoid 30 exceeds the initial setload of the spring 137, the spring 137 is deformed, and relativemovement of the second rod 36 with respect to the first rod 136 isstarted. Thus, the locking portion 26 of the second rod 36 is separatedfrom the auxiliary valve seat 26 c and the auxiliary valve 27 c isopened. Further, when the second rod 36 is driven, the spring 137 isdeformed, the pressing portion 26 d of the locking portion 26 pressesthe flange portion 24 d, and the pressure-sensitive body 24 iscontracted, so that it is possible to bring the auxiliary valve 27 cinto a fully opened state. When the pressure-sensitive body 24 iscontracted by a predetermined amount, a projected portion 24 h of theflange portion 24 d and a projected portion (not shown) provided in thepartition adjusting portion 24 f are brought into contact with eachother, deformation of the pressure-sensitive body 24 is stopped, and themovement of the second rod 36 is also stopped.

The movement of the first rod 136 and the second rod 36 and the movementof the valve portions of the valve element 20 are described above. Next,actions of the capacity control valve 1 and the variable capacitycompressor will be described based on FIG. 3. First, a control state ofthe capacity control valve 1 will be described. The control state is astate where the auxiliary valve 27 c is in a closed state, the openingdegree of the main valve 27 b is set to an opening degree determined inadvance, and pressure of the suction chamber of the variable capacitycompressor is controlled to be a set value Pset. In this state, thefluid of the suction pressure Ps from the suction chamber of thevariable capacity compressor passes from the first communication passage11, the first valve chamber 14, and the communication groove 136 fthrough to the intermediate communication passage 29, flows to aninternal space 28 surrounded by the locking portion 26 of the second rod36 and the pressure-sensitive body 24, and acts on thepressure-sensitive body 24. As a result, the main valve portion 21 c isstopped at a position where force in the valve opening direction by thespring 37, force by the solenoid 30, and force by the pressure-sensitivebody 24 to be extended and contracted in accordance with the suctionpressure Ps are balanced, and the pressure of the suction chamber of thevariable capacity compressor is controlled to be the set value Pset.However, even when the opening degree of the main valve 27 b is set tothe opening degree determined in advance, there is sometimes a casewhere the pressure Ps of the suction chamber is varied with respect tothe set value Pset due to disturbance, etc. For example, when thepressure Ps of the suction chamber is increased to be more than the setvalue Pset due to disturbance, etc., the pressure-sensitive body 24 iscontracted and the opening degree of the main valve 27 b is decreased.Thereby, since the Pd-Pc flow passage is narrowed down, an amount of thefluid of the discharge pressure Pd flowing in from the discharge chamberto the crank chamber is reduced and pressure of the crank chamber islowered. As a result, a tilting angle of a swash plate of the compressoris increased, a discharge capacity of the compressor is increased, anddischarge pressure is lowered. On the contrary, when the pressure Ps ofthe suction chamber is decreased to be lower than the set value Pset,the pressure-sensitive body 24 is extended and the opening degree of themain valve 27 b is increased. Thereby, since the Pd-Pc flow passage isincreased, the amount of the fluid of the discharge pressure Pd flowingin from the discharge chamber to the crank chamber is increased and thepressure of the crank chamber is increased. As a result, the tiltingangle of the swash plate of the compressor is decreased, the dischargecapacity of the compressor is reduced, and the discharge pressure isincreased. In this way, by the capacity control valve 1, it is possibleto control the pressure of the suction chamber of the variable capacitycompressor to be the set value Pset.

Next, a liquid coolant discharge state of the capacity control valve 1will be described based on FIG. 4. After the compressor is stopped for along time, a liquid coolant (made by cooling and liquefying a coolantduring abandonment) is accumulated in the crank chamber. Thus, in orderto ensure predetermined discharge pressure and a predetermined dischargeflow rate after start-up of the compressor, there is a need fordischarging the liquid coolant as soon as possible. At the time ofliquid coolant discharge, since pressure of the third valve chamber 16communicating with the crank chamber and the suction pressure Ps arehigh pressure, and the pressure-sensitive body 24 is contracted, theauxiliary valve 27 c is opened. By opening the auxiliary valve 27 c, itis possible to discharge the liquid coolant from the crank chamber tothe suction chamber via the Pc-Ps flow passage. However, as discharge ofthe liquid coolant progresses, the pressure of the crank chamber and thesuction pressure Ps are lowered. Thus, the opening degree of theauxiliary valve 27 c is gradually decreased. Therefore, it takes time tocompletely discharge the liquid coolant. Meanwhile, in the capacitycontrol valve 1 of the present invention, by driving the solenoid 30 inthe forward direction and pressing the pressure-sensitive body 24 by thelocking portion 26 of the second rod 36, it is possible to forciblymaintain the auxiliary valve 27 c in a fully opened state. Thus, anopening degree of the auxiliary valve portion 23 d is not changed fromstart of the liquid coolant discharge to completion of the liquidcoolant discharge, and it is possible to discharge the liquid coolantfrom the crank chamber to the suction chamber via the Pc-Ps flow passagefor a short time.

Conventionally, at the time of a liquid coolant discharging operation,focus is placed only on how quickly discharge of the liquid coolant iscompleted. Thus, there is sometimes a case where an engine load becomesexcessive during the liquid coolant discharging operation. With thecapacity control valve 1 according to the present invention, even at thetime of the liquid coolant discharge, it is possible to rapidly drivethe valve element 20. At the time of the liquid coolant discharge,actions of the capacity control valve 1 when the engine load is reducedwill be described.

In a case where the engine load is rapidly reduced at the time of theliquid coolant discharge, the solenoid 30 is turned off and magneticattracting force Fsol between the core 32 and the plunger 35 is operatedto be zero. Since settings is made to cancel upward pressure anddownward pressure acting on the valve element 20 at the time of theliquid coolant discharge, regarding major force acting on the valveelement 20 at the time of the liquid coolant discharge, the biasingforce of the spring 37 acting in the valve opening direction of the mainvalve 27 b, and the total force of biasing force of the spring 137acting in the valve closing direction of the main valve 27 b and themagnetic attracting force Fsol of the solenoid 30 are balanced. When themagnetic attracting force Fsol of the solenoid 30 becomes zero, thebiasing force of the spring 37 acting in the valve opening direction ofthe main valve 27 b becomes dominant, and the second rod 36 is movedupward. As a result, the second rod 36 is rapidly pushed up, the lockingportion 26 is brought into contact with the adapter 23, the valveelement 20 is driven in the valve opening direction of the main valve 27b, and the main valve 27 b is rapidly fully opened. When the main valve27 b is fully opened, a coolant amount flowing from the dischargechamber of the compressor to the crank chamber through the Pd-Pc flowpassage is increased, the pressure Pc in the crank chamber is increased,and the compressor is operated by the minimum capacity. In this way, asthe time of the liquid coolant discharge, even in a state where theauxiliary valve 27 c is in an opened state and no force acts on thevalve element 20 from the pressure-sensitive body 24, it is possible toreduce the load of the compressor and hence it is possible to reduce theengine load even at the time of the liquid coolant discharge.

In the control state where the pressure of the suction chamber of thecompressor is controlled to be the set value Pset by the capacitycontrol valve 1, and in a case where the load of the engine is to bereduced, by bringing the solenoid 30 into a non-energized statesimilarly to the above description, the main valve 27 b is brought intoa fully opened state, the coolant amount of the Pd pressure flowing fromthe discharge chamber of the compressor to the crank chamber through thePd-Pc flow passage is increased, and the compressor is operated by theminimum capacity, so that it is possible to perform an operation withwhich the load of the engine is reduced.

In this way, the initial set load of the spring 137 is set to be largerthan the drive force of the solenoid 30 at the time of controlling thecapacity control valve 1. Thus, in a state where the main valve 27 b isopened, the spring 137 is hardly deformed. Therefore, the valve element20 connected to the first rod 136 and the second rod 36 are integrallydisplaced. Thus, the capacity control valve 1 can stably control theopening degree of the main valve 27 b. As the time of the liquid coolantdischarge of the capacity control valve 1, in a case where the driveforce of the solenoid 30 exceeds the initial set load of the spring 137,the spring 137 is deformed, the second rod 36 is relatively moved withrespect to the first rod 136, and the locking portion 26 of the secondrod 36 is separated from the auxiliary valve seat 26 c, so that it ispossible to forcibly open the auxiliary valve 27 c. Thereby, at the timeof the liquid coolant discharge, it is possible to maintain theauxiliary valve 27 c in a fully opened state irrespective of thepressure of the third valve chamber 16 and the suction pressure Ps.Thus, it is possible to discharge the liquid coolant from the crankchamber to the suction chamber via the Pc-Ps flow passage for a shorttime.

The embodiment of the present invention is described with the drawingsabove. Specific configurations are not limited to the embodiment but thepresent invention also includes changes and additions within the rangenot departing from the gist of the present invention.

In the above embodiment, the first pressure of the first valve chamber14 is the suction pressure Ps of the variable capacity compressor, thesecond pressure of the second valve chamber 15 is the discharge pressurePd of the variable capacity compressor, and the third pressure of thethird valve chamber 16 is the pressure Pc of the crank chamber of thevariable capacity compressor. However, the present invention is notlimited to this but with the first pressure of the first valve chamber14 being the pressure Pc of the crank chamber of the variable capacitycompressor, the second pressure of the second valve chamber 15 being thedischarge pressure Pd of the variable capacity compressor, and the thirdpressure of the third valve chamber 16 being the suction pressure Ps ofthe variable capacity compressor, it is possible to respond to variousvariable capacity compressors.

REFERENCE SIGNS LIST

-   -   1 capacity control valve    -   10 valve main body    -   11 first communication passage    -   12 second communication passage    -   13 third communication passage    -   14 first valve chamber    -   15 second valve chamber    -   15 a main valve seat    -   16 third valve chamber    -   17 valve hole    -   20 valve element    -   21 main valve element    -   21 a shut-off valve portion    -   21 c main valve portion    -   23 adaptor    -   23 d auxiliary valve portion    -   24 pressure-sensitive body    -   24 a bellows    -   24 d flange portion    -   26 locking portion    -   26 c auxiliary valve seat    -   26 d pressing portion    -   27 a shut-off valve    -   27 b main valve    -   27 c auxiliary valve    -   29 intermediate communication passage    -   30 solenoid    -   31 electromagnetic coil    -   32 core    -   35 plunger    -   36 second rod    -   136 first rod    -   37 spring (second biasing member)    -   137 spring (first biasing member)    -   Fsol magnetic attracting force    -   Ps suction pressure (first pressure) (third pressure)    -   Pd discharge pressure    -   Pc control chamber pressure (third pressure) (first pressure)    -   Pset suction pressure set value

The invention claimed is:
 1. A capacity control valve that controls aflow rate or pressure of a variable capacity compressor in accordancewith a valve opening degree of a valve portion, the capacity controlvalve being characterized by comprising: (i) a valve main body having: afirst communication passage through which a fluid of first pressurepasses, a first valve chamber communicating with the first communicationpassage, a second communication passage arranged adjacent to the firstcommunication passage, the second communication passage through which afluid of second pressure passes, a second valve chamber communicatingwith the second communication passage, a third communication passagethrough which a fluid of third pressure passes, a third valve chambercommunicating with the third communication passage, and a main valveseat arranged in a valve hole which provides communication between thesecond communication passage and the third communication passage; (ii) avalve element having: an intermediate communication passage providingcommunication between the first communication passage and the thirdcommunication passage, a main valve portion arranged in the second valvechamber, and an auxiliary valve portion arranged in the third valvechamber and at an end of the intermediate communication passage; and(iii) a pressure-sensitive body arranged in the third valve chamber andextending or contracting in accordance with surrounding pressure; (iv) asolenoid having: an electromagnetic coil, a plunger, a core having asecond cylindrical through hole in an axial direction and arrangedbetween the plunger and the valve main body, a first rod arranged insidethe second cylindrical through hole of the core and having a firstcylindrical through hole in the axial direction, a second rod arrangedinside the first cylindrical through hole of the first rod, and a firstspring and a second spring arranged between the plunger and the core,wherein the first rod has one end driven by the plunger via the firstspring, and another end coupled to the valve element, the second rod hasone end coupled to the plunger, and another end coupled to an auxiliaryvalve seat, the first rod driven by the plunger via the first springalternatively opens and closes the valve hole by detaching and touchingthe main valve portion from and to the main valve seat, respectively,and the second rod driven by the plunger alternatively opens and closesthe intermediate communication passage by detaching and touching theauxiliary valve portion from and to the auxiliary valve seat,respectively.
 2. The capacity control valve according to claim 1,characterized in that the first pressure is suction pressure of thevariable capacity compressor, the second pressure is discharge pressureof the variable capacity compressor, and the third pressure is pressureof a crank chamber of the variable capacity compressor.
 3. A method forcontrolling a capacity control valve, characterized by comprising thestep of: by using the capacity control valve according to claim 2,making the main valve portion from a closed state to an opened statewhen the auxiliary valve portion is in an opened state.
 4. The capacitycontrol valve according to claim 1, characterized in that the firstpressure is pressure of a crank chamber of the variable capacitycompressor, the second pressure is discharge pressure of the variablecapacity compressor, and the third pressure is suction pressure of thevariable capacity compressor.
 5. A method for controlling a capacitycontrol valve, characterized by comprising the step of: by using thecapacity control valve according to claim 1, making the main valveportion from a closed state to an opened state when the auxiliary valveportion is in an opened state.
 6. The capacity control valve accordingto claim 1, characterized in that the first spring is arranged betweenthe first rod and the second rod and has an initial set load in adirection of biasing the main valve portion in a valve closing directionin a manner that the first rod and the second rod move while maintainingtheir relative positions when a drive force of the solenoid is not morethan the initial set load, and the second rod moves relative to thevalve element when the drive force of the solenoid exceeds the initialset load.